Asteroids - Comets - Meteoroids
- 1. Vagabonds of the Solar System Asteroids, Comets, and Meteoroids
- 2. A search for a planet between Mars and Jupiter led to the discovery of asteroids • Thousands of asteroids with diameters ranging from a few kilometers up to 1000 kilometers. • Most orbit within the asteroid belt between the orbits of Mars and Jupiter • Asteroids are small chunks of ROCK or Metal that revolve around the sun..
- 6. The asteroids are the relics of planetesimals that failed to accrete into a full-sized planet, thanks to the gravitational effects of Jupiter and other Mars-sized objects.
- 7. The sun and Jupiter are keeping the asteroids in balance because both are pulling in opposite directions. Jupiter’s gravity helped shape the asteroid belt
- 8. Often asteroids become CAPTURED because a planet’s gravity pulls them in orbit. Jupiter’s gravity captures asteroids in two locations, called Lagrangian points, along Jupiter’s orbit
- 10. Asteroids occasionally collide with one another, • causing them to break up into smaller fragments
- 11. Asteroids are found outside the asteroid belt— and have struck the Earth • These outside belt asteroids, called near-Earth objects, move in highly elliptical orbits that cross the path of Mars and Earth • If such an asteroid strikes the Earth, it forms an impact crater whose diameter depends on both the mass and the speed of the asteroid
- 13. An asteroid may have struck the Earth 65 million years ago, possibly causing the extinction of the dinosaurs and many other species
- 14. Comets are a mixture of ice, dust, and a small amount of rock in the form of a sphere. Comets move around the sun in highly elliptical orbits.
- 16. Comets are hard to find unless they are near the SUN because… • As they approach the sun, the entire comet vaporizes (Sublimes). • The temperature increases due to the suns solar radiation. • The nucleus of ice vaporizes (Solid to a Gas). • Solar winds push the gas and dust away to form dust and ion tail.
- 17. PARTS of a COMET NUCLUES: Center of a comet made of ice, gas, and dust COMA: Thick envelope of water, CO2, and dust that melts/sublimes out of the nucleus. DUST TAIL: Solid rocky particles being pushed away by the sun’s solar wind. ION TAIL: Frozen CO2 being vaporized and pushed away by the sun’s solar wind.
- 18. An ion tail and a dust tail extend from the comet, pushed away from the Sun by the solar wind and radiation pressure
- 22. Comets formed from left over material during the formation of the solar system. • Most comets are found in the Kuiper belt beyond Pluto. • The Kuiper Belt is part of a vast cloud in near interstelar space called the Oort Cloud.
- 24. Halley’s Comet – pt.1 (SD)
- 25. Comets eventually break apart, and their fragments give rise to meteor showers When Earth passes through the tail of a comet, this is when we typically see “Shooting Stars”
- 26. Small rocks in space are called meteoroids Meteoroids: – A meteoroid is a chunk of rock that is smaller than an Asteroid. – Average about 100 m in diameter. – It is part of an asteroid or left over from comet debris. – Revolves around the sun – Located outside Earth’s atmosphere.
- 27. Meteors – When a meteoroid comes into contact with Earth’s Atmosphere. • Meteors burns up due to the intense friction of Earth’s Atmosphere. • We see a shooting star in the sky when this occurs.
- 28. Meteorites are meteoroids that go through the entire atmosphere without burning up completely, making landfall. (A meteor that makes it through the atmosphere)
- 29. Meteorites cause craters on Earth Surface
- 30. Meteorites are classified as stones, stony irons, or irons, depending on their composition
- 32. Irons and stony irons are fragments of the core of an asteroid that was large enough and hot enough to have undergone chemical differentiation, just like a terrestrial planet
- 33. Some meteorites retain traces of the early solar system • Some stony meteorites come from the crust of such differentiated meteorites, while others are fragments of small asteroids that never underwent differentiation • Rare stony meteorites called carbonaceous chondrites may be relatively unmodified material from the solar nebula • These meteorites often contain organic material and may have played a role in the origin of life on Earth • Analysis of isotopes in certain meteorites suggests that a nearby supernova may have triggered the formation of the solar system 4.56 billion years ago
- 34. • Fragments of “burned out” comets produce meteoritic swarms • A meteor shower is seen when the Earth passes through a meteoritic swarm